In Chemical Mystery #7, a can of Coca-Cola was observed to sink in one container of water and yet float in another! This trick made use of the fact that the density of water changes with temperature.
Q: Does an unopened can of soda pop float or sink in water?
A: It depends!
See if you can figure out what is happening in this twist on the classic floating-and-sinking soda can experiment.
Inspired by Tom Kuntzleman*, I started using mysteries in my chemistry curriculum this past year. The first mystery I shared with my students was burning water. While my magician skills aren't perfect, I was able to get the students asking questions and proposing hypotheses. For my IB students, it really allowed me to delve into a number of topics (e.g. combustion, intermolecular forces, polarity, density). And thus an idea was born: Using one mystery per topic. In this blog post I'll discuss my beginning effort to find or develop a mystery for each topic within the IB Chemistry curriculum.
Solution to Chemical Mystery #6 is presented. Also, concepts related to the chemical can crush demo are briefly discussed.
Can you figure out how this experiment works?
Flinn Scientific has a great elearning video series. Many of the videos have master teachers demonstrating some great labs and techniques that they do in the classroom.
I am fascinated by the chemistry of pennies. I have tried several experiments found in the Journal of Chemical Education.
This is a series of experiments, PhET Interactive Simulation activities, and clicker questions to relate macroscopic and molecular representations of homogenenous solutions. Graphing skills are also used.
The reaction of a copper penny (minted pre-1982) and concentrated nitric acid (15 M) is shown. Red-brown nitrogen dioxide is generated and some of the copper dissolves to form a blue solution of copper(II) nitrate.
